Mighty Thor (Jane Foster)
Mjolnir (a.k.a. The God Tempest) – also in flashbacks to its origin
Lord High Librarian of the Halls of All-Knowing in Omnipotence City

Ulik the Rock Troll – only in flashback to when he was young
Rock Troll warriors (none named) – all only in flashback
Dwarves of Nidavellir (none named) – all only in flashbacks
All-Father Odin (with a patch over his right eye) – only in flashbacks

The Storm (a.k.a. the God Tempest, the Mother of Thunder) – a sentient cosmic thunderstorm the size of a galaxy that had existed since the dawn of time – only in flashback to how it ended up trapped in Mjolnir

gods of Asgard (none named) – only in flashback
Thor Odinson – only in a flashback to when he was a boy

Note: In this issue the Lord High Librarian states that Omnipotence City was built four billion years ago by the first of the elder gods. This is different from Thor: God of Thunder #3, in which Thor’s narrative claimed that Omnipotence City was “built twelve billion years ago, after the first great war of the gods.” Was this a mistake? Or did Gorr change history when he travelled into the past to kill the first god?